#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<math.h>
int main()
{
	double n = 0;
	int m = 0;
	double ret = 0;
	while (scanf("%lf %d", &n, &m) != -1)
	{
		int i = 1;
		while (i <= m)
		{
			ret += n;
			n = sqrt(n);
			i++;
		}
		printf("%.2lf", ret);
	}
	return 0;
}